This application is related to and claims priority from Japanese Patent Applications No. 2001-366706 filed on Nov. 30, 2001, No. 2002-196053 filed on Jul. 4, 2002, No. 2002-223638 filed on Jul. 31, 2002, and No. 2002-284142 filed on Sep. 27, 2002, the contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a hybrid compressor device suitable for a refrigerant cycle system mounted in an idling stop vehicle, where a vehicle engine is stopped when the vehicle is temporally stopped.
2. Description of Related Art
Recently, the market for an idling stop vehicle has been increased to save fuel consumption. In a case where a compressor is driven only by an engine of the vehicle, when the vehicle is temporarily stopped, its engine is stopped, so that the compressor, driven by the engine, is also stopped in a refrigerant cycle system. In order to overcome this problem, in a conventional hybrid compressor device disclosed in JP-A-2000-130323 (corresponding to U.S. Pat. No. 6,375,436), driving force of the engine is transmitted to a pulley through a solenoid clutch, and one end of a rotational shaft of the compressor is connected to the pulley. Further, the other end of the rotational shaft of the compressor is connected to a motor. Accordingly, when the engine is stopped, the solenoid clutch is turned off, and the compressor is driven by the motor, so that the refrigerant cycle system can be operated regardless of the operation of the engine.
However, the hybrid compressor device requires the solenoid clutch for switching a driving source of the compressor between the engine in the operation of the engine, and the motor in the stop of the engine. Therefore, production cost of the hybrid compressor device is increased. Further, the compressor is operated by one of both the driving sources of the engine and the motor. Therefore, a discharge capacity of the compressor and a size thereof are need to be set based on a maximum heat load of the refrigerant cycle system in a driving force range of each driving source. For example, when a cool down mode (quickly cooling mode) is selected directly after the start of the vehicle in the summer, the heat load of the compressor becomes in maximum. Thus, the discharge capacity of the compressor and the size thereof are set so as to satisfy the maximum heat load, thereby increasing the size of the compressor.
The present invention has been made in view of the above problem, and its object is to provide a hybrid compressor device capable of reducing its production cost and its size, while ensuring cooling performance after the stop of a vehicle engine.
It is an another object of the present invention to provide a hybrid compressor device which has improved reliability while being produced in low cost.
According to the present invention, a hybrid compressor device includes a pulley rotated by a vehicle engine that is stopped when the vehicle is temporally stopped, a motor rotated by electric power from a battery of the vehicle, a compressor operated by driving force of the pulley and driving force of the motor, a transmission mechanism for changing and transmitting rotation force, and a control unit for adjusting the rotational speed of the motor. Here, the compressor is for compressing refrigerant in a refrigerant cycle system provided in the vehicle. The transmission mechanism is connected to a rotational shaft of the pulley, a rotational shaft of the motor and a rotational shaft of the compressor, so that a rotational speed of the pulley and a rotational speed of the motor are changed and transmitted to the compressor. In the hybrid compressor device, the pulley, the motor and the compressor are disposed to be rotatable independently. Further, the control unit changes the rotational speed of the compressor by adjusting the rotational speed of the motor with respect to the rotational speed of the pulley. Accordingly, the rotational speed of the compressor can be increased and decreased with respect to the rotational speed of the pulley, thereby changing a discharge capacity of the compressor. When the heat load of the refrigerant cycle system becomes maximum as in a cool down mode (quickly cooling mode), the discharge amount of the compressor can be effectively increased by increasing the rotational speed of the compressor than the rotation speed of the pulley by the adjustment of the rotation speed of the motor. Therefore, the size of the compressor and the discharge amount of the compressor can be set smaller. On the contrary, the discharge amount of the compressor can be reduced by reducing the rotational speed of the compressor than the rotation speed of the pulley by the adjustment of the rotation speed of the motor. Therefore, the compressor can quickly corresponds to the heat load of the refrigerant cycle system in a normal cooling mode after the end of the cool down mode. Furthermore, even when the engine is stopped due to idling stop and the rotational speed of the pulley becomes zero, the compressor can be operated by operating the motor. Therefore, even in the idling stop time, cooling operation can be maintained in low cost without using a solenoid clutch.
Preferably, the transmission mechanism is a planetary gear including a sun gear, a planetary carrier and a ring gear, and the rotational shafts of the pulley, the motor and the compressor are connected to the sun gear, the planetary carrier and the ring gear of the planetary gear. Here, the connection between the rotation shafts of the pulley, the motor and the compressor, and the sun gear, the planetary carrier and the ring gear of the planetary gear can be arbitrarily changed. For example, the rotational shaft of the compressor is connected to the planetary carrier, the rotational shaft of the pulley is connected to the sun gear, and the rotational shaft of the motor is connected to the ring gear. Alternatively, the rotational shaft of the pulley is connected to the planetary carrier, the rotational shaft of the motor is connected to the sun gear, and the rotational shaft of the compressor is connected to the ring gear. Alternatively, the rotational shaft of the motor is connected to the sun gear, and the rotational shaft of the compressor is connected to the ring gear, and the rotation shaft of the compressor is connected to the planetary carrier.
Preferably, a lock mechanism is provided for locking the rotational shaft of the motor when the motor is stopped. In this case, when the compressor is operated by driving force of the pulley while the motor is stopped, the control unit detects fluctuation of an induced voltage of the motor by detecting leakage fluctuation of magnetic flux of the motor generated due to rotation of the transmission mechanism connected to the compressor. Accordingly, when a trouble such as lock is caused in the compressor, the rotation of the transmission mechanism is reduced or becomes zero, so that the fluctuation of the induced voltage becomes smaller. Thus, an abnormal operation of the compressor can be readily detected by effectively using the fluctuation of the magnetic flux of the motor.
The hybrid compressor device of the present invention can be applied to a vehicle having an engine that is stopped in a predetermined running condition of the vehicle having a driving motor for driving the vehicle.
On the other hand, in a hybrid compressor where a compressor for compressing refrigerant in a refrigerant cycle system is operated by at least one of a driving unit and a motor, the compressor includes a suction area into which refrigerant before being compressed is introduced, a discharge area into which compressed refrigerant flows, and an oil separating unit for separating lubrication oil contained in refrigerant from the refrigerant and for storing the separated lubrication oil in the discharge area. Further, a transmission mechanism is disposed between the compressor and at least any one of the driving unit and the motor, for changing a rotational speed of the at least one of the driving unit and the motor, to be transmitted to the compressor. In addition, both of the motor and the transmission mechanism are disposed in a housing, an oil introducing passage is provided so that the lubrication oil stored in the discharge area is introduced into the housing through the oil introducing passage, and an inner space of the housing communicates with the suction area of the compressor through a communication passage.
Accordingly, lubrication oil contained in refrigerant is separated from the refrigerant by the oil separating unit, and the separated lubrication oil is introduced into the housing. Further, the introduced lubrication oil is circulated from the housing into the suction area of the compressor. Therefore, lubrication oil can be always supplied to the transmission mechanism in the housing, thereby improving reliability of the transmission mechanism. Further, since the motor is also disposed in the housing, the motor can be cooled by the lubrication oil, thereby improving reliability of the motor. Because lubrication oil is separated from the refrigerant by the oil separating unit, refrigerant, circulated in the refrigerant cycle system, contains almost no lubrication oil. Therefore, lubrication oil is not adhered to a heat exchanger such as an evaporator provided in the refrigerant cycle system, thereby preventing heat-exchange efficiency of the heat exchanger from being reduced.
Preferably, the housing is disposed to accommodate the compressor, the motor and the transmission mechanism. Further, the housing has a suction port, from which the refrigerant is sucked into the compressor, at a side where the motor and the transmission mechanism are disposed. Therefore, the motor and the transmission mechanism can be effectively cooled by the refrigerant introduced into the housing.
More preferably, the oil introduction passage is a first decompression passage through which the discharge area of the compressor communicates with the inside of the housing while pressure is reduced from the discharge area of the compressor toward the inside of the housing, and the communication passage is a second decompression passage through which the inside of the housing communicates with the suction area of the compressor while the pressure is reduced from the inside of the housing toward the suction area of the compressor. Therefore, the lubrication oil can be smoothly circulated between the compressor and the housing.